Automatic train control system



Aug, 11, 1931. E. c. SASNETT AUTOMATIC TRAIN CONTROL SYSTETJ Filed Jan.9, 1928 on a siait 31.

l atentecl Aug. 11, 1931 oni'rso siA TION F PENNSYLVAI-IIA AUTGMATICTRAIN Application filed January 9,

This invention relates to railway signalling and has particularreference to automatic train controlling systems of thecode-continuous-indication type. The system herein shown is based on thesystem shown and claimed broadly in my copending application Serial No.24,544, filed April 20, 1925.

Referring to the accompanying drawing, which shows diagrammatically asystem embodying the invention: designates a stretch of track divided byinsulated joints 11 into blocks. The usual track relays 12 are connectedacross the rails the entrance ends of the blocks, and located at eachblock station are a line relay 13, a track battery 14. a battery 15 ofrelatively high voltage (which may be the battery for operating thetrack signals, and a. continuous current shunt field motor 16. Theapparatus at only one block station is shown in full, but of course thisapparatus is duplicated at all the block stations.

As indicated, the motor armature is rigid with a shaft on which isfixed, or to which is geared, an alternating current generator 18. Themotor is connected to battery through front cont-acts 24 of line relay13, so that the motor is inactive when this relay is deenergized, whichis the normal condition. Alternator 1S connected by conductors 29 toconductors 32 through suitable non-inductive resistances 33. Formed onshaft 20, or suitably geared thereto, is a worm 21 which meshes with aworm wheel 30 fast Fixed on shaft 31 are three disks a, a, and 0, formedwith cam projec tions adapted respectively to operate the movablecontacts of switches m, y and .2, these contacts being connected toconductors The stationary contacts of switch :0 are connected byconductors and to the track rails at the exit end of block. Thestationary contacts of switch 1 are connected to conductors 36, whichare connected to hack contacts 37 of the track relay, the movablecontacts cooperating with these back contacts being connected byconductors 38 to the track rails at a suitable point in advance of theentrance end of the block. The stationary contacts oonrnon SYSTEM 1928.Serial No. 245,377.

of switch 2 are connected by conductors 42 to th front contacts 43 ofthe track relay, the movable contacts cooperating with these t contactsbeing connected by conduc- 4G to thetrack rails at the exit end of theblock.

Under normal conditions, the motor 16, alternator 18 and the switchmechanism as sociated therewith are inactive, the circuit of the motorbeing open at front contacts 24 of line relay 1;}, and the track battery14 is connected across the rails at the exit end of the blocl: throughback contacts 44 of the line relay and conductors 45 and 40. lVhen atrain enters the block, the circuit of line relay 13 is closed at backcontacts 46 of the track relay connected to the block entered, and theline relay therefore picks up, disconnect-- ing the track battery 14 andconnecting battery 15 to motor 16. The motor accordingly rotates,driving alternator 18 and the cam discs (t, Z; and c, the alternatorapplying an alternating potential to the movable contacts of switches00, 3 and 2. Under safe traliic conditions the track relay 12'associated with the switches is energized, and therefore the stationarycontacts of switches on and 2 only are connected to the track rails, thestationary contacts of switch 00 being connected to the rails directlythrough conductors 34 and 35, and the stationary contacts of switch 2being connected to the rails through conductors 42, front contacts 43,and conductors 40. It will be observed that the cam projection of diska, adapted to operate the movable contacts of switch 2U, extends througha rel atively large angle, while the disc 0 is pro vided with vorelatively short cam projections which are adapted to effectsuccessively two short closures of switch 2 at each revolution of shaft31. These short cam projections on disc 0 are angularly spaced from thelong projection on disc a, so that there will occur at each revolutionof shaft 31 two short closures of switch 2 followed by a relatively longclosure of switch :0.

When a train enters a block under caution conditions, thetrack relayimmediately in advance being deenergized, the motor, alternator andswitch mechanism will be set in operation as before, but the stationarycon tacts of switch 2 will be disconnected from the track rails at frontcontacts 43, while the stationary contacts of switches 09 and y will beconnected to the rails, the stationary contacts of switch ;2 beingconnected by conductors 36, back contacts 37 and conductors 38; and thestationary contacts of switch a: being connected directly by conductors34 and 35. It will be observed that the cam projection of disc 6,adapted to operate the movable contacts of switch y, is angularlydisplaced from the long cam projection of disc a. The switches 02 and ytherefore will operate under caution conditionsto apply alternatingvoltage for a short period at the point where conductors 38 areconnected to the rails and then for a relatively long period at the exitend of the block, at each revolution of shaft 31.

From the foregoing it will be understood that a vehicle travelling onthe track will receive under clear conditions two short impulses ofalternating current followed by a long impulse, periodically, and thatwhen a Vehicle enters the block under caution conditions it will receiveone short impulse followed by a long impulse, periodically, until itpasses the point of connection of conductors 38, when it will receiveonly a succession of long impulses.

At the left of the drawing a vehicle V is indicated by a pair of wheelsand an axle As is usual in inductive train control systems of thecontinuous indication type, the vehicle is provided with coils carriedadjacent the rails in advance of the first pair of wheels, so as to havethreaded therethrough the alternating flux of the current flowing in therails. These coils are connected to the winding of a relay 51, and ifdesired an amplifier A may be inserted between the coils and the relay.

Relay 51 controls a code responsive mechanism which is adapted torespond to codes consisting of one or more short impulses followed by along impulse. This mechanism comprises four small quick acting relays,52, 53, 5-1 and 55, a slow acting relay 58, and two slow release relays59 and 60.

It will be understood from the foregoing that under clear trafiicconditions, relay 51 will be energized intermittently by two shortimpulses followed by a long impulse, this code being recurrently orperiodically received under clear conditions. Assuming all the magnets5255 to be deenergized, as shown, upon reception of the short impulserelay 51 will pick up, closing the circuit of slow acting relay 58 andrelay 52. The circuit of relay 58 is from battery B, conduc -:.:r 62,front contact 6-3, conductor 64, relay and conductors and 66. Thecircuit of relay 52 is from battery B, conductor 62, front contact- 63,conductor 67, back contact 68 of relay 58, conductor 56, relay 52, and

conductors 69 and Go. Qlle slioi t 11 pulses will not aliect relay 5?,si e relay 58 is slow in picking up, but relay will pick up and close asticlt circuit for which is from battery B, conductors 62 and 70, backcontact 71 slew acting ay 5S, conductors 72 and (ii, front contact "3 ofrelay 52, conductor 74:, the winding of relay 52 and conductors 59 and66v When relay Bl drops at the end of the short impulse, it clot s thecircuit of magnet 53, which s from battery B, conductor (32, backcontact 75, conductor 76, back contact conductor 76, nt contact i"? ofrole ctor 78, the *inding of relay 53 .c doctors 7'2) and (36. Whenrelay 53 piv ip it cio. a stick Ci for itself, which is from battery B,conductors G2 and TO, hack contact 71., conductor 72 conductor 81, frontcontact 8.4 conductor 23, the winding of relay a8, and coiuiluctors 79and 6(5. ll hen the ext impu is received, relay picks up, circuit beingfrom battery l3, conductor (32, front contact 33, conductor (57, backcontact (58, conductors 56 and 57, front contacts 85 and 86 conductor8?, the winding of relay 5%, and conductors a d (36. When relay 9 lpicksup it closes a s circuit for itself, which is from b: "tery l5,conductors (32 and 70, back contact '71, conductors 72 and 8t, conductor259, front contact 90, conductor 91,, the winding of relay 5-51; and conluct n-;-1 88 and 56. v hen relay iil drops at the end of second shortimpulse, the circuit of relay 5;) is clt c; this circuit being frombattery 3, conductor (32, baclt contact 75, conductor 76, back contact76, conductor front contacts '77,

to 92 and 93, conductor 9-l, the winding of relay F5, and conductors 95and 66. hen relay picks up it closes a stick circuit for from battery B,conductors 62 and 70, ac contact 71, conductors 72 and 80, conductor 96,front contact 97, conductor 98, aiul conductors 95 and (36. The nextimpulse received is the long impulse. T his long iin} of SlllllCle:

duration to cause slow acting relay 58 pin; up, which effects first theclosure of its front contact 113 and ther: the opening of its backcontact 71, the armature of this relay being provided with upg xer 1lower spring contacts which cause t. r f i contac to close in advance ofthe o i the back contact. closes it completes the circuit of slow release relays 59 and 60. The cir= t is from battery B, con-din; 62 andTl, front contact 113, conductor ill, front co tacts 115, 116 and ll?relays 52, 5 and 54:, respectively, conductor 118, no wiudirg of relay59 and conductors 119, 120, and (36. The circuit of relay 60 is froml'iattery ii, conductors 62 and 70, front contact 113, conductor 11%,front contacts 115, 11G, 11'? and noted that when the r y 58 picks upupon reception of the long impulse all the quick acting relays 5255 willopen their front contacts, since the stick circuits of all these relaysare opened at back contact 71. Upon reception of the next code of twoshort and one long impulse, the relays 5255 will successively pick up,another impulse will be sent through the slow release relays 59 and 60and then the relays 52-55 will again drop. These operations will berepeated continually unt er clear traffic conditions, and the periodicimpulses sent through relays and 60 will be efi'ective to cause theserelays as to continuously hold close: their front contacts. lVhen bothrelays 59 and 60 are holding closed their front contact he circuit of aclear lamp 126 is closed, this circuit being obvious from the drawing.

When a vehicle enters a block tion conditions, it will receive a codeconsisting of one short impulse followed by a long impulse until it pase the point of connection of conductor a) under caus 38. .lll cause therelays 52, 53 and 5 ergized and simultan impulse being so: t thio lay 59at the completion be clear from the foregono longer sent through sl thisrelay will open its close its back contacts, open of clear lamp 126 andmo which will effect only the intermittent eration of slow relay 58 andquick acting relay 52, which of course will be ineffective to send animpulse through his release relay 59. This latter clay will thereforeopen its front contacts and close its back contact, opening the circuitof caution lamp 127 and closing the circuit 012. a danger lamp 128. 7The system of course can be combined with a speed controlled mechanismto impose a maximum speed when clear signal 126 is displayed; anintermediate speec when caution 7 signal 127 is displayed, and a lowspeed when danger signal 128 is disp-layed. As such mechanism forms initself no part of the present invention and is well known in the art, Ideem it unnecessary to show such mecnanism.

Having described my invention, 1 claim: 1. An automatic train controlsystem comprising in combination, a track divide-" blocks, means forinerntently connect n a source of alternating current across the trackrails at the exit one of a block under clear traffic conditions and forintermittently connecting said source the rails at the exit end of theblock and also across the rails at an intermediate point of the blockunder mum conditions the connection of the source at said intermediatepoint occurring asynchronously with the connection at the exit end,:andra vehicle having train control mechanism responsive to the currentimpulses flowing in the track rails.

2. An automatic train control system comprising in combination a trackdivided'into block-s, normally inactive means for intermittentlyconnecting a source of alternating current across the rails at the exitend of a block when a vehicle enters that block under clear. t-ra tlicconditions, and for intermittently connecting said source across therails at the exit 'end of the block and also across the rails at anintermediate point of the block when a vehicle enters the block undercaution conditions, the connectionsof the source at said intermediatepoint occurring asynchronously with the connections at the exit end, anda vehicle having train control mechanism responsive to the currentimpulses flowing in the track rails.

3. An automatic train control system comprising in combination, a trackdivided into insulated blocks, a track relay connected across the rails.at the entrance end of each block, a track battery connected across therails at the exit end of each block, normally inactive means fordisconnecting the track battery from a block and for intermittentlyconnecting a source of alternating current across the rails at the exitend of said block when a vehicle enters that block under clear traflicconditions and for intermittently connecting said source across therails at the exit end of the block and also across the rails at anintermediate point of the block when a vehicle enters said block undercaution conditions, the connections of the source at said intermediatepoint occurring asynchronously with the connections at the exit end, anda vehicle having controlling mechanism responsive to the currentimpulses flowing in the track rails.

4:. An automatic train control system comprising in combination, a trackdivided into insulated blocks, means for producing a code of impulses inthe track rails of block under clear trafic conditions and a differentcode of impulses under caution traffic conditions, said clear code beingproduced by intermittently connecting a source of energy across thetrack railsat the exit end only of the block and said caution code beingproduced by connecting the same source of energy across the track railsat the exit end asynchronously with the connection of said source at anintermediate point of the block, and a vehicle having controllingmechanism responsive selectively to the two codes of impulses.

5. An automatic train control system comprising in combination, a trackdivided into insulated blocks, a track relay and a track batteryconnected respectively across the rails at the entranceand exit ends'ofeach block, means for producing a code of alternating current impulsesin the track rails of a block under clear traiiic conditions and adifferent code of alternating current impulses under caution tra-flicconditions, said clear code being produced by intermittently connectinga source of alternating current energy across 1Q the track rails at theexit end only of the block and said caution code being produced acrossthe track rails at the exit end asynchronously with the connection ofsaid source across the rails at an intermediate point in the block, anda vehicle having controlling mechanism responsive selectively to the twocodes of impulses.

6. An automatic train controlling system is) comprising in combination,a track divided into insulated blocks, a track relay and a source ofcurrent connected across the track rails at the entrance and eXit endsof each block respectively, normally inactive means as forintermittently connecting source of en.-

ergy across the track rails of a block when a vehicle enters that blockunder clear traffic conditions to produce a periodic code of impulses inthe rails, the code consisting of a relatively long impulse and aplurality of short impulses, and a vehicle controlling means responsiveto said code, said means comprising a relay on the vehicle responsive tothe impulses, a slow acting relay the circuit of which is closed whensaid vehicle relay is energized, a series oi quick acting relaysconsecutively energized as said vehicle relay is energized and.deenergized, stick circuits respectively for said quick acting relays,all of said stick circuits including a back contact of said slow actingrelay, and a vehicle controlling circuit including in series frontcontacts of said quick acting relays and a front contact of said slowacting relay.

1!; 7. An automatic train control system comprising in combination withmeans to produce in the track rails a recurrent code of impulsesconsisting of a relatively long impulse and at least one short impulse,a rehicle on the track having a relay responsive to the impulses, a slowacting relay the circuit of which is closed when said vehicle relay isenergized, and a plurality of quick acting relays consecutivelyenergized as said vehicle relay is ene gized and deenergized, stickcircuits respec ely for said quick act ing relays, all of saidstickcircuits including a back contact'ot said slow acting relay, and avehicle controlling circuit including in series front contacts of saidquick acting relays and a front contact of said slow acting relay.

8. An automatic train control system comprising in combination a trackdivided into insulated blocks, a track relay connected across the railsat the entrance end of each block, a track battery connected acr ss therails at the exit end of each block, a normally inactive motor and analternator and switch mechanism driven by the motor associated with eachtrack relay, means actuated when a vehicle enters a block to disconnectthe track battery from that block and to set in operation the motorassociated therewith, said alternator being connected across the 7 trackrails at the exit end of said block thron h the switch mechanismassociated therewith and said switch echanism operating to connect thealternator iitermittently to produce in the ra s predetermined codes ofimpulses according to 'traflic condition, and a vehicle havingcontrolling means selectively responsive to the codes of im pulses.

9. An an:

battery connected across the rails respectively at the entrance and exitends or each block, means for producing a code of impulses in the trackrails of a block under clear trailic conditions and a different code01'? impulses under caution tratfic conditions, said clear code beingproduced by intermittently connectin a source of en a'gy across thetrack rails at the cXi"; end only of the block and said caution codebeing produced by connecting the same source oi energy across the trackrails at the exit end asynchronously with the connections of said sourceacross the rails at an intermediate point in the block, and a vehiclehaving controlling mechanism responsive selec nvely to the two codes ofimpulses.

10. An automatic train control system comprising in combination, a trackdivided into insulated blocks, a track relay connected across the railsat the entrance end of each block, a track battery connected across therails at the exit end of each block, a. normal- 1y inactive motor and analternator driven thereby associated with each track relay, meansactuated when a vehicle enters a block to disconnect the tract batteryfrom that block and to set in operation the motor associated therewith,and trailic controlled means for connecting the alternator driven bysaid motor across the track rails at the exit end of said block.

11. An automatic train control system comprising in combination, a trackdivided into insulated blocks, a track relay connected across the railsone end of ach block a source of current connected across the rails atthe other end of each block, a normally inactive motor and an alternatordriven thereby associated with each track relay, means actuated when avehicle enters a block to disconnect the source i'rom that block and toset in operation the motor associated therewith, and traffic controlledmeans for connecting the alternator driven by said motor across therails of said block.

12. An automatic train control system comprising in combination, a trackdivided into insulated blocks, a track relay connected across the railsat one end of each block, a source of current connected across the railsat the other end of each block, a normally inactive motor and analternator and switch mechanism driven by the motor associated with eachtrack relay, means controlled by each track relay and actuated when avehicle enters the corresponding block to set in operation the motorassociated therewith, and means for connecting each alternator with therails of the corresponding block through the associated switch mechanismto produce in the rails a code of periodically varied altern atingcurrent.

13. In combination, a stretch of railway track, a source of directcurrent, an alternating current generator operated by current from saidsource, means for supplying current from said generator to the rails ofsaid stretch, and means for at times periodically interrupting suchalternating current at different frequencies depending upon traflicconditions.

14. In combination, a stretch of railway track, a source of directcurrent, apparatus receiving energy from said source for generatinguninterrupted alternating current, a contact arranged to operateperiodically at a predetermined frequency, and means including saidcontact for supplying current from said apparatus to the rails of saidstretch.

15. In combination, a stretch of railway track, a source of directcurrent, apparatus receiving energy from said source for gen eratinguninterrupted alternating current, a plurality of contacts arranged tooperate periodically at different frequencies, and means for supplyingalternating current from said apparatus to the rails of said stretchover a selected one of said contacts depending upon traflic conditions.

16. In combination, a. stretch of railway track, a source of directcurrent, a motor operated by current from said source, an alternatingcurrent generator driven by said motor, a contact operatedintermittently by said motor, and means including said contact forsupplying alternating current from said generator to the rails of saidstretch.

17. In combination, a stretch of railway track, a source of directcurrent, a motor operated by current from said source, an alternatingcurrent generator driven by said motor, a plurality of contacts, meansdriven by said motor for operating said contacts at difierentfrequencies, and means for sup plying current from said generator to therails of said stretch over a selected one of said contacts.

signature.

EDWARD C. SASNETT.

